The major role of the Clinical Core will be to identify, clinically characterize and expand as far as is genetically useful and clinically possible, families in which parkinsonism segregates. Efforts will also be made,to identify patients without an apparent family history of parkinsonism. Blood samples obtained will be passed to the Genetic Core using the Progeny computerized system for conveying clinical information. The Progeny system is already in place. Confidentiality of biographical information is maintained by coding the samples prior to passing them on to the Genetic Core. Many families with parkinsonism have already been identified by the PI and his co-investigators, and these cases are also enrolled in the Core. The Clinical Core Director's responsibilities will include obtaining appropriate IRB approval for these studies. Communication with the overall PI of the grant and Pl's of other Cores and Projects will be maintained by monthly conferences organized by the Clinical Core. These conferences will use the Mayo Clinic satellite system for direct communication with other sites involved in the Clinical Core activities. In addition, the Director of this Core will conduct weekly or biweekly conferences with the coordinators of the Core to discuss progress, train, and to resolve any difficulties that the coordinators encounter in their work. Subsidiary aims of the Core will be to organize neuropathologic examination of family members, both to confirm and delineate the diagnosis and also to obtain frozen tissue for molecular investigations. Following identification of causal genes for parkinsonism via familial linkage studies and their repercussions in human neuropathological specimens, a long-term objective of the Core is to orchestrate the use of such molecular targets in therapeutic trials in affected and "at risk" human individuals.